Gas engine



E. M. TUCKER June 22, 1937.

4 Sheets-Sheet 1 6 o 2 4 3 a a s 2 2 n 7 8 2 2 INVENTOR EM Tucker ATTORNEY June 22, 1937 E. M. TUCKER GAS ENGINE 4 Sheets-Sheet 2' y L-ze INVENTOR EM TLLC/fl)! ATTORNEY June 22, 1937.

E. M. TUCKER GAS ENGINE Filed July 30, 1934 4 Sheets-Sheet 3 Q 39 38 v J 14 INVENTOR E. M Tl a Cl: 61'

June 22, 1937. E. TUCKER GAS ENGINE Filed July 50, 1934 4 Sheets-Sheet 4 lllll INVENTOR E. M Tucker jams;

ATTORNEY Patented June 22, 1937 UNITED STATES PATENT OFFlCE Claims.

This invention relates to gas engines of the two-cycle type and while it has certain features in common with the structure shown in my copending application for patent, Serial No. 595,699,

filed February 29, 1932, it represents considerable improvement in construction thereover. Also the present application is a continuation in part of my copending application, Serial No. 688,973, filed February 11, 1933.

This engine has as an essential feature a pair of pistons movable in cooperating relation but in opposite directions, means to initially compress a fuel mixture and then admit the same between the pistons at the proper time, and

means to again compress the admitted mixture and to then fire the compressed and confined charge.

The problems naturally incident to mounting V of a spark plug in a reciprocating member have been successfully met in a simple and efficient manner so that a standard type of spark plug may be used; high compression and great efficiency coupled with coolness of the pistons and other parts in operation have been obtained; and

less possibility of fouling the new mixture with the burnt gases is provided. The features of construction whereby the above desirable ends are attained form the major objects of the present invention.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly eifective for the purpose for whichit is designed.

These objects I accomplish bymeans of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several Views: V

, Figure 1 is a transverse section of the engine showing the pistons in their firing position.

Figure 2 is a similar view of the engine showing the pistons in their exhausting and intaking positions. Figure 3 is a sectional elevation of the engine with the pistons in the position shown in Figure 1.,

Figure 4 is a sectional plan on the line 44 of Figure 2. g

Figure 5 is a similar view on the line 5--5 of Figure 2.

Referring now more particularly to the characters of reference on the drawings, the outer a thorough and more elficient scavenging, with fixed cylinder of the engine comprises an upper chamber l and a lower relatively small cylinder portion 2 supported on the upper portion 3 of the crank case, the cylinder being provided with heat radiating fins 4 or similar heat transfer 5 means.

Slidable in the cylinder 2 is the cylinder-piston 5 having an enlarged ringed head portion 6 engaging the wall of the chamber I. Opposite trunnions 1 project from the piston 5 intermediate its 10 ends, said trunnions projecting into opposed runways 8 formed with the cylinder 2. Connecting rods 9 engage the trunnions and spaced cranks E0 on the drive shaft H which as usual is journaled in the crank case 3. 15

A piston I2 is slidable in the piston 5, said piston being connected to another connecting rod 13 which engages a crank 14 on the shaft H disposed between the cranks H! at an angle of thereto, and having the same throw. With this 20 arrangement it will be seen that the two pistons travel in opposite directions, either away from or toward each other.

The construction of the piston l2 differs from that ordinarily used in gas engine practice in that 25 the compression rings I5 are below the wrist pin, there being only a single carbon scraping ring l6 above the pin, which is as close to the head of the piston as possible. The ends of the wrist pin bore in the piston are tightly sealed with plugs 30 ll, as shown in Figure 3 so that there is no possibility of gas leaking past the same, and is of course a necessity with this ring arrangement. This construction, with the particular intake and exhaust passage arrangement now to be described, better provides against loss of compression than would otherwise be the case.

It also removes or eliminates carbon, provides for better lubrication and insures longer life or less wear of the contacting surfaces, since the 40 main rings are below the zone of high heat, and do not subject to undue expansion. The piston may be split vertically if desired, from the top down to adjacent the rings I5 as at S, so as to oil?- set the expansion due to heat.

The cylinder 2 is provided with an exhaust port 18 adjacent its lower end and between the runways 8, said port being positioned to register with a port I9 in the piston 5 when the latter is at the topmost stroke position, as shown in Figure 2. 50 The piston I2 is then at the bottom of its stroke, and said ports then communicate with the lower end of a passage 20 formed in the piston l2 on the adjacent side and extending to the upper end thereof. 55

An intake passage 2! adapted for connection to a carburetor communicates with the cylinder I adjacent the top and on the side thereof opposite the exhaust ports. A check valve 22 of suitable character in the passage opens in the direction of the cylinder. Tapping said passage be tween the cylinder and the valve is another passage 23 which leads down to a termination at the bore of the cylinder 2 substantially in alinement with but opposite the port 88. At this end said passage is adapted to register with a port 24 in the piston 5, which in turn is adapted to register with the lower end of a passage 25 in the piston I2. This latter piston extends to the top of the piston on the side thereof opposite the passage ill, the upper end of the connecting rod l3 projecting between said passages. This registration of the ports and passages is had at the same time that the port It registers with the passage 2!], or when the pistons are at their opposite limit of travel.

The lower end of the passage 3 is in the form of a hollow saddle block 26 separate from the cylinder 2, said saddle following the contour of the piston 5 as shown in Figure 5, and is enclosed in a housing 21 formed with said cylinder. The block is yieldably and adjustably held against the piston by a spring 28 bearing against the outer face of the block while another spring til in the housing El below the block engages and holds the saddle upwardly against the adjacent fixed portion of the passage 23. In this manner the possibility of a gas leakage is prevented, and wear between the adjacent surfaces of the piston 5 and the passage block are taken up as it occurs.

By reason of this arrangement it will be seen that as the piston 5 descends the valve 22 opens, allowing a mixture to be drawn into the chamber I above said piston. At the same time mixture previously taken into the piston 5 is being compressed by the approach of the heads of the pistons 5 and I2 toward each other. When the piston heads are at their limit of approach the compressed mixture is fired, as will be seen. later, forcing the pistons apart and of course imparting a driving impulse to the shaft 4 I.

As the piston 5 moves up the mixture in the chamber I is compressed so that as the port 24 and passage 25 finally register with the passage 23, such compressed mixture rushes into the piston 5 through the passage 25. At the same time the fired charge passes out through the then registering exhaust ports. The diameter of the chamber I is considerably greater than that of the interior of the piston 5, while the stroke of said piston 5 is such that its head approaches very close to the head of the chamber I at the topmost point of its stroke. In this manner a very large charge of mixture may be drawn into the chamber I, while at the same time such charge is very highly compressed and completely expelled into the passage 2|. and thence into the piston 5.

By reason of the use of the opposed passages in the piston 5 for the incoming and outgoing gases, there is no great contamination of the fresh mixture by the exhaust gases such as is the case with the ordinary construction, in which the incoming mixture immediately and directly contacts with the exhaust gases. Nor is there any possibility of any of these fresh gases blowing through the exhaust port as is the case with ordinary construction. With this new arrangement a large percentage of the fresh charge is kept isolated from the outgoing gases and scavenging is improved. Also the elimination of the usual and ordinarily necessary gas deflecting baflle on the piston head enables the head of the piston l2 to approach closer to the head of the piston 5.

The charge thus forced into the piston 5 is fired in the following manner:

Mounted in and projecting radially from said piston. is a standard spark plug 3i], whose spark points are exposed inwardly of the piston and which are positioned so as to communicate with the lower end of the passage 25 when the pistons are in their closest limit of travel, as shown in Figure 1. The boss Si in the piston 5 in which the spark plug is mounted projects through a Vertical slot 32 in the cylinder 2, said slot being of course as long as the stroke of the piston. In-

asmuch as the saddle block and spark plug are in the same vertical plane so as to both register with the piston passage 25, the portion of the passage 28 above the block extends to one side of the spark plug as shown in Figure 4.

The slot and spark plug are completely enclosed in a housing 33 formed on the cylinder 2, said housing having an opening 361 facing the slot 32 and larger than the diameter of the plug so that the latter can be easily withdrawn or inserted when alined with said opening. The opening is positioned to aline with the plug when the latter is in its port registering and firing position, and is normally closed by a removable cover plate 35 of insulation material. This plate has a binding and terminal post member 35 mounted therein, the inner end of which is adapted to almost contact the outer end of the usual central plug electrode when the plug is in the above named position. The outer end of the member 36 is adapted for connection to a wire 3? leading from a distributor and a source of current in the conventional manner.

The plug therefore initially ignites the mixture at the lower end of the passage 5, which insures a relatively slow propagation of the flare or explosion and I have found that this arrangement promotes smoothness of operation and eliminates knocking and unduly heavy strains on the connecting rods, crank shafts, and engine parts gen-- erally. The spark points being located on theintake side of the engine are exposed to the. cooling elfect of the incoming upwardly moving mixture when the pistons are widely separated and this also tends to scour and keep the points clean of carbon.

Opposed air intake and outlet check valve units 38 and 39 respectively are mounted at the bottom of the cylinder I as shown in Figure 3. These communicate with the atmosphere and with the interior of the cylinder 1 below the piston head 6, and provide for the admission, circulation and discharge of cooling air, atmosphere, with each reciprocation of the pistons. The wallsof the piston 5, where they are subjected to thegreatest heat from the interior explosion are therefore continually kept in a cool condition.

The trunnion runways 3 must actually open into the cylinder I to permit of the passage of the trunnions I when the piston 5 is being removed. This is on account of the fact that the enlarged head 6 of said piston can only be withdrawn by an upward movement. The check valve units 38 and 39 therefore while in eifect a part of the cylinders E and Z are actually made in the form of blocks separate and removable from the cylinders and are disposed so as to close the upper ends of the runways and prevent direct communication between the cylinder l and the crank case of the engine.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

1. A two cycle engine comprising an outer piston and an inner piston slidable therein, said pistons being arranged for reciprocation in opposite directions simultaneously and having heads on one end to form an enclosed chamber for mixture therebetween, a fixed cylinder in which the outer piston is slidable, said piston having an intake port in one side uncovered by the inner piston when said pistons are in a certain position relative to each other, a passage saddle block mounted in and separate from the cylinder open to and engaging a portion of the periphery of the outer piston and positioned to register with said port when the pistons are in said certain position, means holding the block against the outer piston with a predetermined pressure, and a mixture intake passage member communicating with the interior of the block.

2. In a two-cycle engine, a piston, a mixturechamber member in which said piston is slidable, said member having a mixture intake port in one side, and a passage formed in the piston and extending from the head thereof to a termination at one side of the piston toward the end opposite the head in position to register with the port when the piston moves to the inner end of its stroke, and igniting means mounted in said member in position to register with the peripheral end of the passage when the piston is at the outer end of its stroke.

3. In a two-cycle engine, a piston, a mixturechamber member in which said piston is slidable,

- said member having opposed intake and exhaust ports in its opposite sides lying in substantially the same plane lengthwise of said member, and

separate passages formed in the piston and extending from the head thereof to terminations on opposite sides of the piston toward its inner end in position to register with the opposed ports when the piston moves to the inner end of its stroke.

4. In combination, in a gas engine a piston, a member in which said piston is slidable, said member having a port in one side below the topmost position of the piston, gas passage means to communicate with the port from outside said member, a passage leading downwardly from the top of the piston and opening to the side thereof to communicate with said port when the piston is in said topmost position, rings about the piston below the bottom termination of said passage whereby to prevent the leakage of gas downwardly from the passage, the piston having a wrist pin bore above the rings extending to the opposite sides of the piston, and compression tight sealing plugs in the ends of the bore to prevent leakage of gas through the bore from the top of the piston; the piston being split from side to side from the upper end thereof to a termination above the rings.

5. A two cycle gas engine comprising an outer piston and an inner piston slidable therein, said pistons arranged for reciprocation in opposite directions simultaneously and having heads on one end to form an enclosed chamber for mixture therebetween, a fixed cylinder in which the outer piston is slidable, said piston having an intake port in one side uncovered by the inner piston when said pistons are in a certain position relative to each other, a chamber on the cylinder open to a portion of the periphery of the outer piston and positioned to register with the intake port when the pistons are in said certain position, a mixture intake passage member leading to said chamber, and spring pressed gas sealing means in the chamber engaging the exposed portion of the outer piston and having a passage therethrough to establish communication between the intake passage and said port when the pistons are in said certain position.

EMMIT'I M. TUCKER. 

